8 9. What is m derived filter? Derive the relevant equation of m derived low pass N-08 16

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1 EC 2305: Transmission Lines and Wave Guides-Question Bank UNIT-I/ PART A S.No Question Exam 1. For a symmetrical network, define propagation constant and characteristic impedance. M What are the advantages of m-derived filters? M A constant-k T-section high pass filter has a cutoff frequency of 10 KHz. The design N-10 impedance is 600 ohms. Determine the value of L. 4. What are the advantages of m-derived filters? N-10 N If Zoc =1000Ω and Zsc =360Ω, determine the Zo of the symmetrical network. N What are the disadvantages of constant-k prototype filter section? M Find L and C of a low pass T section constant-k filter having a cutoff frequency of 1.KHz M-09 and load of 500ohms.. What are the demerits of constant k filters? N-0 9. Design a prototype low pass filter T section of design impedance Ro =500Ω and cutoff frequency fc=2000hz N Compare constant K and m-derived filters. M Determine the value of C required by a prototype high pass T-section filter having a cutoff M-0 frequency of 1KHz to work into a 600ohms load resistance. 12. Draw a simple High-pass filter section and give the values of circuit elements. N Draw a simple Band-pass filter network and give the values of circuit elements. N What are called cut-off frequencies in the design of filters? M What is constant-k filters? M What are the properties of band elimination filter? M How the resonant frequency is chosen in the m-derived high pass filters? M What is constant-k network? N How to obtain constant-k high pass filter? N Define characteristics impedance of a network. M Define constant-k filters. M Why constant K filters are also known as prototype filters? N Define cutoff frequency N A T section low pass filter has series inductance of 0mH and shunt capacitance of µf. M-05 Determine the cutoff frequency and the nominal impedance. 25. What are called constants K filters and what are the demerits? M What are the characteristics of an ideal filter? N Why m-derived filter of L-sections are used as terminations of composite filters? N What are the merits of m derived filters? M Define neper. What is its relation with Decibels? M-04 UNIT-I/ PART B S.No Question Exam Marks 1. Derive the relevant equations of m-derived low pass filter and design m-derived T type low pass filter to work into load of 500Ω with cut off frequency at 4 KHz and Peak attenuation at 4.15 KHz. M M- Apr/ May; N- Nov/ Dec Page 1 of 1

2 S.No Question Exam Marks 2. Explain the structure and application of crystal filter. Design a low pass filter M with cut off at 2600 Hz to match 550Ω. Use one derived section with infinite attenuation at 250Hz. 3. (i)design a m-derived T-section low pass filter having a cutoff frequency of 5000 Hz and a design impedance of 600 ohms. The frequency of infinite attenuation is f=1.25f c. N-10 (ii)draw and explain the operation of crystal filters. 4. (i)design a constant K- T-section band pass filter with cutoff frequencies of 1 KHz and 4 KHz. The design impedance is 600 ohms. (ii)draw a constant K- T-section band elimination filter and explain the N-10 operation with necessary design equations. 5. Design a composite low pass filter to meet the following specifications. The N filter is to be terminated in 500Ω resistance. It is to have a cutoff frequency of 100Hz with high attenuation at 1065Hz and 1250Hz. 6. Discuss the characteristics impedance of symmetrical networks and filter N fundamentals. 7. (i)draw and explain the operation of constant-k T-section band elimination filter with necessary expressions and also present the design equations. (ii) In a constant-k T-section band pass filter, the ratio of capacitances in the M shunt and series arm is 100:1 and resonant frequency of both the arms is 1000Hz.Find the bandwidth of the filter.. (i) Outline the steps involved in the design of composite high pass filter. (ii)design an m-derived π-section high pass filter with a cutoff frequency (fc) of 5 KHz and frequency of infinite attenuation at 1.25fc.Assume design impedance of 600ohms. M What is m derived filter? Derive the relevant equation of m derived low pass N-0 16 filter. 10. The series arm Z,of a filter consists of a 0.5µF capacitor in series with an inductor of 0.5H.If Ro =500Ω,determine the elements in the shunt arm and the manner in which they MAY be connected. Find the frequency of resonance fo and pass band. N (i)design a m-derived high pass filter (both T and sections) with a cut off M-0 10 frequency of 10KHz. Design impedance is 500ohms and m=0.4. (ii)what do you mean by composite filter? Discuss its construction, design and characteristics briefly (i)with a neat diagram explain the operation of a constant-k band pass filter. M-0 12 Derive the equation of resonance. Develop expression for the circuit elements used in the series and shunt arms of the filter. Consider a T-section. (ii)draw a constant-k(t-section) band elimination filter. Write design equations Design and derived m-derived low-pass filter with relevant diagrams. N Design a constant-k low pass filter and illustrate with a diagram for variation N of α and β with frequency for the low-pass section. 15. (i)explain the design of a low-pass filter using a typical cut-off frequency M-07 desired and the load resistance to be supplied. (ii)determine the cutoff frequency for the low-pass filter shown in fig. M- Apr/ May; N- Nov/ Dec Page 2 of 1

3 S.No Question Exam Marks L1 L /2mH C1 0.5uf 0/2mH Fig. 16. Design a low pass filter (both and T-sections) having a cutoff frequency of 2KHz to operate with a terminated load resistance of 500Ω 17. Discuss the theory of band elimination filter for both T and π configurations and also plot the variation of reactance with respect to frequency. 1. (i)design a m-derived low-pass filter having cutoff frequency of 1KHz,design impedance of 400Ω and the resonant frequency of 1100Hz. (ii)design an m-derived high pass filter with a cut-off frequency of 10 KHz; design impedance of 5Ω and m= (i)explain with diagram the manner of variation of Zo (characteristic impedance) over the pass band for the T and π networks. (ii)a π-section filter network consist of a series arm inductance of 10mH and two shunt arm capacitances of 0.16µF each. Calculate the cut-off frequency and attenuation and phase shift at 12 KHz. What is the value of nominal impedance in the pass band. 20. (i)design a low pass filter (both π and T-sections)having a cutoff frequency of 2KHz to operate with a terminated load resistance of 500Ω. (ii)design a high pass filter having a cutoff frequency of 1 KHz with a load resistance of 600Ω. 21. (i)design a Band pass filter to operate into input and output resistance of 100Ω and have a pass band between 4.KHz and 5.2KHz. (ii)in a constant-k band pass filter, the ratio of the shunt arm capacitance to the total series arm capacitance is 100:1.The frequency of resonance of both the arm is 1000Hz.calculate the B.W of the filter. 22. Design a composite LPF to meet the following specifications: fc =2000Hz, =2050Hz, Ro=500ohms, Where fc=the cut-off frequency, =frequency of infinite attenuation, Ro=Design impedance Use T section. 23. (i)derive the design equation of constant K Band pass filter. (ii)design a m derived LPF for fc =1kHz, =1050Hz and R=600ohms 24. (i)determine the characteristics impedance of symmetrical T network. (ii) Explain the characteristics of symmetrical networks while connecting like elements in it. (iii)design the elements of a low pass T filter with termination 500ohms and cutoff frequency 1000Hz. 25. (i)derive the m derived T network from prototype T network. (ii)find the characteristics impedance of the symmetrical T network is the series arm impedance is 10+j30 and shunt arm impedance is 50-j100. N N M-06 M- Apr/ May; N- Nov/ Dec Page 3 of 1 M-06 M-06 N -05 M M-05 N M-04

4 S.No Question Exam Marks 26. Design a low pass composite filter for the following specifications. Cut-off M frequency fc =2 khz. Frequency of infinite attenuation =2050Hz Load impedance R k =500Ω.Use T section to develop the n composite filter. UNIT-II/ PART A Sl.No. Question Exam 1. How can distortion be reduced in a transmission line? M A transmission lie has Zo = Ω and is terminated in Z R = 100 Ω. Calculate M-11 the reflection loss in db. 3. Define delay distortion. N Write the expressions for the phase constant and velocity of propagation for N-10 telephone cable. 5. What is the relationship between characteristics impedance and propagation M-10 constant? 6. What is meant by distortion less line? M Define phase distortion. N-09. What is meant by inductance loading of telephone cables? N What is propagation constant? Which are its two components? M State the condition for distortion less line. M Briefly discuss the difference between wavelength and period of a sine wave. N Find the attenuation and phase shift constant of a wave propagating along the line N-0 whose propagation constant is 1.04x Find the reflection coefficient of a 50Ω transmission line when it is terminated by a M-0 load impedance of 60+j40 Ω. 14. Define reflection loss. M Define propagation constant of a transmission line. N Calculate the characteristic impedance of a transmission line if the following N 07 measurements have been made on the line Zoc = Ω and Zsc = Ω. 17. What is frequency distortion? M Calculate the load reflection coefficient of a perfectly matched line with no M 07 reflection from load. 19. Define characteristic impedance of a transmission line. N How much inductive loading is required to make a 16-gauge cable distortion less? N-06 The line parameters are R = 42.1 Ω/km, G = 1.5 µ mho, C = µf/km and L = 1 mh/km. 21. List the various types of transmission lines used in practice. Extra 22. What are the important parameters of a Transmission Line? Extra 23. Define Attenuation and phase constant. Extra 24. What is reflection factor? Extra 25. Explain insertion loss. Extra 26. Write the expression for the characteristic impedance and propagation constant for a Extra M- Apr/ May; N- Nov/ Dec Page 4 of 1

5 line of zero dissipation. 27. Define wavelength of a transmission line? How is it related to the phase velocity? Extra UNIT-II/ PART B Sl.No. Question Exam Marks 1. Derive the equation of attenuation constant and phase constants of M transmission lines in terms of line constants R,L,C and G and explain the significance of reflection coefficient and insertion loss. 2. A generator of 1V, 1 KHz supplies power to a 100 Km open wire line M terminated in 200 Ω resistance. The line parameters are R= 10 Ohms/Km, L=3.mH/Km, G = 1 x 10-6 mho/km, C= µf/km. Calculate the impedance, reflection coefficient, power and transmission efficiency. 3. (i)a transmission line has the following per unit length parameters : L = 0.1 µh, R = 5 ohms, C= 300 pf and G= 0.01 mho. Calculate the propagation constant and characteristic impedance at 500 MHz. (ii)derive the conditions required for a distortion less line. N (i) The characteristic impedance of a uniform transmission line is ohms at a frequency of 00 MHz. At this frequency the propagation constant is 0.054( j0.99. Determine R and L. (ii) Explain the reflection on lines not terminated in characteristic impedance with phasor diagrams. Define reflection coefficient and N reflection loss. 5. (i) Derive the expression for the input impedance of a lossless line() (ii) Draw the L-type equivalent circuit model of a two-conductor transmission line and derive the transmission line equations M (i) Discuss the reflection Coefficient of different types of transmission lines. (ii)a transmission line operating at 10 6 rad/s has α=db/m,β=1rad/m and Zo =60+j40Ω, and is 2meter long. If the line is connected to a M-10 source of 10 0 o, Zg =40Ω and terminated by a load of 20+j50Ω,determine the current the middle of the line 7. (i) Derive expressions for the attenuation and phase constants of a transmission line in terms of the line constants R,L,G and C.(10) N (ii)the constants of a transmission line are R=6ohms/km,L=202mH/km,C=0.005x 10-6 F/km and G=0.25x mho/km. Determine the characteristic impedance and propagation constant at 100Hz. (6). Derive an expression for the input impedance of a transmission line. Hence obtain the input impedance for a lossless line.() (ii) Write a short note on reflection factor and reflection loss.() N Derive the expression for voltage and current at any on a transmission line in terms of receiving end voltage and current. (b) A line has R= 100 Ω/km, L= 0.001H/km, G=1.5 X 10-6 mho/km, and M-09 C= µf/km. Determine the characteristic impedance, propagation constant for f=1000 Hz, E s =1.0 volts and length=100km. 10. (a) Derive Campbell s equation. M-09 M- Apr/ May; N- Nov/ Dec Page 5 of 1

6 Sl.No. Question Exam Marks (b) A generator of 1V, 1KHz supplies power to a 100 km transmission line terminated in a 200Ω resistance. The line parameters are R= 10 Ω/km, L=3. mh/km, G=1 µ mho/km and C=0.005 µf/km. Calculate the input impedance and reflection coefficient 11. Derive the general transmission line equations for voltage and current at N-0 16 any point on a line 12. (a) Write a brief note on frequency and phase distortions. (b) The characteristic impedance of a 05m-long transmission line is Ω, the attenuation constant is 74.5X10-6 Np/m and the phase shift N-0 constant is 174X10-6 rad/m at 5KHz.Calculate the line parameters R, L, G, C per meter and the phase velocity on the line. 13. (a) Explain in detail about the Waveform distortion and also derive the condition for distortion less line. (b) Derive the expression for transfer impedance of a Transmission M-0 Line. 14. (a) A parallel-wire transmission line is having the following line parameters at 5 KHz. Series resistance (R = 2.59x10-3 Ω/m), series inductance (L = 2 µh/m), shunt conductance (G = 0Ω/m) and capacitance between conductors (C = 5.56 pf/m). Find the characteristic impedance, attenuation constant,(α Np/m), phase shift constant (β rad/m), velocity of propagation and wavelength. (b) A 2 meter long transmission line with characteristic impedance of 60 M-0 + j40 Ω is operating at (ω) 10 6 rad/sec has attenuation constant of Np/m and phase shift constant of 0 rad/m. If the line is terminated by a load0 of 20 + j50 Ω. Determine the input impedance of this line. 15. (a) Derive the expression for the input impedance of a transmission line. (b) A cable has the following parameters: R=4.75 Ω/km, L=1.09 mh/km, G=3.75 µ mho/km and C= µf/km. Determine the N-07 characteristic impedance, propagation constant and wavelength for a source of f=1600 Hz and Es=1.0 volts 16. (a) A cable has been uniformly loaded by an inductance such that wl>>r. assuming leakage conductance to be nil, deduce an expression for attenuation and phase constant without neglecting R. (b) A transmission line has the following parameters per km R=15Ω, C=15µf, L=1mH and G=1µmho. Find the additional inductance to give N-07 distortion less transmission. Calculate attenuation and phase constant for the loaded line 17. (a) Discuss in detail about Inductance loading of Telephone cables and derive the attenuation constant (α), phase constant (β) and velocity of signal transmission (v) for the uniformly loaded cable. (b) Explain in detail about the reflection on a line not terminated in its characteristic impedance (Z 0 ). M (a) A transmission line operating at 500 MHz has Z 0 = 0Ω, α = 0.04 Np/m, β=1.5 rad/m. Find the line parameters series resistance (R Ω/m), M-07 series inductance (L H/m), shunt conductance (Gmho/m) and capacitance between conductors (C F/m). M- Apr/ May; N- Nov/ Dec Page 6 of 1

7 Sl.No. Question Exam Marks (b) A distortion less transmission line has attenuation constant (α) 1.15X10-3 Np/m and capacitance of 0.1 nf/m. The characteristic resistance (L/C) = 50Ω. Find the resistance, inductance and capacitance per meter of the line. 19. (a) Obtain the general solution of a transmission line. (b) A line has R= 10.4 Ω/km, L= 3.67mH/km, G=0.X 10-6 mho/km, and C= µf/km. Determine the characteristic impedance, propagation constant and sending end current for f=1000 Hz, E s =1.0 N-06 volts and length=100km. 20. (a) Discuss the two types of waveform distortion on a transmission line and obtain the condition for distortion less line. (b) A telephone cable 64km long has a resistance of 13 Ω/km and a capacitance of 0.00 µf/km. Calculate the attenuation constant, velocity N-06 and wavelength of the line at 1000Hz. 21. Derive the input impedance of open and short circuited dissipation less Extra line. Illustrate with suitable diagrams the variation of the input impedance as a function of length. 22. Prove that a finite line terminated in Z o behaves like an infinite line. Extra 23. For a Transmission Line terminated in Z o, prove that (i) Z o - Z oc.z sc (ii) Extra tanhγl= Z sc /Z oc. 24. Derive the relationship between Zoc & Zsc Extra UNIT-III/ PART A Sl.No. Question Exam 1. Express standing wave ratio in terms of reflection coefficient. M Mention the application of a quarter wave line. M A lossless line has a characteristic impedance of 400 ohms. Determine the standing N-10 wave ratio if the receiving end impedance is 00+j 0.0 ohms. 4. Write the expressions for the input impedance of open and short circuited N-10 dissipation less line. 5. Distinguish between series stub and shunt stub. M Write the procedure to find the impedance from the given admittance using smith M-10 chart. 7. A low loss line has a characteristics impedance of 400ohms.Determine the standing N-09 wave ration if the receiving end impedance is (650-j475)ohms.. Give the applications of an eighth wave line. N If the reflection co-efficient of a line is , calculate the standing wave ratio. M What is the value of Z o for the dissipation less line? M Give the minimum and maximum value of SWR and reflection coefficient. N Why is the Quarter wave line called as copper insulator? N Distinguish between single stub matching and double stub matching. M What are the applications of the quarter-wave line? N A 50 Ω line is terminated in load Z R = 90 + j60 Ω. Determine the reflection N-07 coefficient. 16. Find the VSWR and reflection coefficient of a perfectly matched line with no M-07 M- Apr/ May; N- Nov/ Dec Page 7 of 1

8 Sl.No. Question Exam reflection from load? 17. Name few applications of half-wave line. M Define standing wave ratio. N Design a quarter wave transformer to match a load of 200 Ω to a source resistance N-06 of 500Ω. The operating frequency is 200 MHz. 20. What are small and zero dissipation lines? Extra 21. List the parameters of open wire line at high frequencies. Extra 22. List the parameters of coaxial wire line at high frequencies. Extra 23. What are standing waves? Define node & antinodes. Extra 24. Why do standing waves exist on transmission lines? Extra 25. What are the applications of smith chart? Extra 26. Why short circuited stub is preferred to open circuited stub? Extra 27. What is the application of quarter- wave matching section and the value of Extra characteristic impedance of the matching section? 2. What are the advantages of double stub matching over single stub matching? Extra 29. Derive the relationship between standing wave ratio and reflection coefficient? Extra 30. What is the need for stub matching in transmission lines? Extra UNIT-III/ PART B Sl.No. Question Exam Marks 1. Explain the technique of single stub matching and discuss operation of M quarter wave transformer. 2. Explain the applications of smith chart. A 30m long lossless M transmission line with Zo = 50Ω operating at 2 MHz is terminated with a load Z L = 60+j40 Ω. If U= 0.6C on the line, find the reflection coefficient, Γ, standing wave ration(s) and the input impedance. 3. (i) Draw and explain the operation of a quarter wave line. (ii) It is required to match a 200 ohms load to a 300 ohms transmission line to reduce the SWR along the line to 1. What must be the characteristic impedance of the quarter wave transformer used for this purpose if it is directly connected to the load? (iii)what are the drawbacks of single stub matching and open circuited stubs? N (i) Draw and explain the principle of double stub matching. (ii) A UHF lossless transmission line working at 1 GHz is connected to an unmatched line producing a voltage reflection coefficient of 0.5(0.66+j 0.5). Calculate the length and position of the stub to match N-10 the line. 5. (i) Discuss the operation of a quarter wave line and illustrate its applications. (ii) A lossless line in air having a characteristic impedance of 300ohms M-10 is terminated by unknown impedance.the first voltage minimum is located at 15cm from the load. The standing wave is 3.3.Calculate the wavelength and terminating impedance 6. (i) A load having an impedance of (450-j600) ohms at 10MHz is connected to a 300ohms line. Calculate the position and length of a short M M- Apr/ May; N- Nov/ Dec Page of 1

9 Sl.No. Question Exam Marks circuited stub to match this load to the line using Smith chart. (ii) What are the drawbacks of single stub matching? Briefly discuss 4 how it is overcome by double stub matching. 7. (i)a 100+j50Ω is connected to a 75Ω lossless line. Find the reflection Coefficient, load admittance and input impedance at the generator using smith chart. (ii)explain the realization of quarter wave transformer. N-09. (i)discuss double stub matching. (ii) Show that the incident and reflected waves combine to produce a standing wave. N Define standing wave ratio and obtain the expression of VSWR in terms of reflection Coefficient. (b) Derive the input impedance of a quarter wave line and discuss its applications. M (a) Obtain the expression for the length and location of a short-circuited stub for impedance matching on a transmission line. (b) A load (50-j100) Ω is connected across a 50Ω line. Design a shortcircuited stub to provide matching between the two at a signal frequency M-09 of 30 MHz using smith chart. 11. A 75 Ω lossless transmission line is to be matched to a resistive load impedance of Z L = 100 Ω via a quarter-wave section. Find the characteristic impedance of the quarter wave transformer. (b)a 50 Ω lossless transmission line is terminated in a load impedance of Z L = (25+j50) Ω.Use the smith chart top find voltage reflection N-0 coefficient, VSWR, input impedance of the line, given that the line is 3.3 λ long and input admittance of the line. 12. A 50 Ω lossless feeder line is to be matched to an antenna with Z L = (75- N-0 16 j20) Ω at 100 MHz using Single Shorted stub. Calculate the stub length and distance between the antenna and stub using smith chart. 13. (a)what is Quarter-wave line? Discuss its application. (b) A 70 Ω lossless line is used at a frequency where wavelength (λ) equals 0 cm terminated by a load of (140+j91)Ω. Find the Reflection M-0 coefficient, VSWR and input admittance using SMITH chart. 14. A 75 Ω lossless transmission line is to be matched with a 100-j0 Ω M-0 16 load using SINGLE stub. Calculate the stub length and its distance from the load corresponding to the frequency of 30 MHz using SMITH chart. 15. (i)deduce the expression for constant S circle for the dissipation less line and explain. (b) A transmission line is terminated in Z L. Measurements indicate that the standing wave minima are 102 cm apart and that the last minimum is N cm from the load end of the line. The value of standing wave ratio is 2.4 and R 0 = 250 Ω. Determine wavelength and load impedance. 16. (a) Explain the procedure for double stub matching on a transmission line with an example. (b) Determine the length and location of a single short-circuited stub to produce impedance match on a transmission line with R 0 of 600 Ω and terminated in 100 N-07 M- Apr/ May; N- Nov/ Dec Page 9 of 1

10 Sl.No. Question Exam Marks Ω. 17. (a) Discuss the application of Quarter-wave line in impedance matching and copper insulators. (b) A 30 m long lossless transmission line with characteristic impedance (Z0) of 50Ω is terminated by a load impedance (ZL)= 60+j40 Ω. The operating wavelength is 90m. Find the reflection coefficient, Standing Wave Ratio and input impedance using SMITH chart. M A 50 Ω transmission line is connected to a load impedance (Z L ) = M j0Ω. The operating frequency is 300MHz. A DOUBLE-stub tuner spaced an eighth of a wave length apart is used to match the load to the line. Find the required lengths of the short-circuited stubs using SMITH chart. 19. (a) Derive the expression for the input impedance of the dissipation less line and thus obtain the expression for the input impedance of a quarterwave line. Also discuss the application of quarter-wave line. N-06 (b) An antenna as a load on a transmission line produces a standing wave ratio of 2. with a voltage minimum 0.12 λ from the antenna terminals. Find the antenna impedance, reflection factor and reflection loss at the antenna if R0 = 300 Ω for the line. 20. (a) Explain single stub matching on a transmission line and derive the expressions for the location and the length of the stub used for matching on a line. (b) Design a single stub match for a load of 150+j225 Ω for a 75Ω line at 500 MHz using SMITH chart. 21. A transmission line has a characteristic impedance of 300 Ω and terminated in a load Z L =150+j150Ω. Find the following using SMITH chart (i) VSWR (ii) Reflection coefficient (iii) input impedance at a distance of 0.1 λ from the load (iv) input admittance at 0.1 λ from the load (v) position of first voltage minimum and maximum from the load. 22. (a) Discuss the applications of Smith chart with suitable illustrations. (b) The transmission line has standing wave ratio S = 2.5 and the volt minimum exists 0.15λ from the load. Find the load and input impedance for a line of 0.35λ lengths. Use smith chart. N-06 EXTRA EXTRA UNIT-IV/ PART A Sl.No. Question Exam 1. The electric field in free space is given by E= 50 cos[10 t +βx] a y V/m. Find the M-11 direction of propagation and β. 2. Define the cutoff frequency for the guided waves. N-10 N For a frequency of 6 GHz and plane separation of 3 cm, find the group and phase N-10 velocities for the dominant mode. 4. Give the examples of guided waves. M-10 M- Apr/ May; N- Nov/ Dec Page 10 of 1

11 Sl.No. Question Exam 5. What is the relationship between group velocity and phase velocity? Give the expression that relates phase velocity [V P ], group velocity [V g ] and free M-10 M-07 space velocity [C]. 6. Give the expression for the cutoff wavelength and propagation constant of TE waves between parallel planes. N Write the expression for the wave of TE and TM waves between parallel planes. N-09. What are the characteristics of TEM wave? What are the characteristics of principal wave? M-09 N-07 N Write Maxwell s equations in point form. M Enumerate the properties of TEM waves between parallel planes of perfect N-0 conductors. 11. Plot the frequency versus attenuation characteristic curve of TM and TE waves N-0 guided between parallel conducting plates. 12. What is Principal wave? M Plot the frequency Vs Wave impedance curve for the waves between parallel M-0 conducting planes. 14. What is the cut-off frequency of TEM wave? M Define the terms phase velocity and group velocity. N Define TE and TM waves/ E and H waves. EXTRA 17. Define energy transport velocity of a wave. EXTRA 1. Why is TE 10 mode is the lowest order TE mode? EXTRA 19. What are TEM waves? EXTRA 20. Write the boundary conditions for TE/TM waves between parallel planes. EXTRA 21. What is meant by dominant mode? EXTRA 22. Write the expression for the attenuation constant for TE/TM/TEM waves in parallel EXTRA plate guide. 23. Define wave impedance. EXTRA 24. Write the expression for the wave impedance for TE/TM/TEM waves in parallel EXTRA plate guide. 25. Can a TM0 mode propagate in a parallel plate guide? Why? EXTRA 26. Draw the field patterns for the TE 10 /TM 10 /TEM wave/mode in a parallel plate EXTRA guide. UNIT-IV/ PART B Sl.No. Question Exam Marks 1. Discuss in detail guided waves between parallel planes with neat M diagram. 2. (i) Explain the transmission of TE waves between parallel perfectly conducting planes with necessary expressions for the field components. (ii) A TEM wave at 1 MHz propagates in the region between conducting planes which is filled with dielectric material of µr =1 and εr = 2. Find N the phase constant and characteristic wave impedance. 3. (i) Explain the reasons for the attenuation of TE and TM waves between parallel planes with necessary expressions and diagrams. N M- Apr/ May; N- Nov/ Dec Page 11 of 1

12 Sl.No. Question Exam Marks (ii) Write brief note on the manner of wave travel and their velocities between parallel planes (i)distinguish between the characteristics of TE and TM waves. (ii)derive the expression for the field components for TM waves between parallel planes. M (i)derive the expression for the field components of TEM waves. (ii) Discuss wave impedance in detail. M Discuss the attenuation of TE and TM waves between parallel planes N with necessary expression and diagram.(16) 7. Discuss the transmission of TM waves between parallel perfectly N conducting planes with necessary expression for the field components.. (a)obtain the solution of field components of TE waves between parallel plates, propagating in Z direction. (b) A pair of perfectly conducting planes is separated by 3.6 cm in air. For TM 10 mode determine the cut-off frequency and cut-off wavelength, M if the operating frequency is 5 GHz 9. (a)derive the expressions for the field components of TEM waves between parallel conducting planes. Discuss the properties of TEM waves. (b) For a frequency of 10GHz and plane separation of 5 cm in air, find the cut-off wavelength, phase velocity and group velocity of the wave M (a)derive the components of Electric and Magnetic field strength between a pair of parallel perfectly conducting planes of infinite extent in the Y and Z directions. The planes are separated in X direction by a meter. (b) A parallel perfectly conducting planes are separated by 5 cm in air N and carries a 10 GHz signal in TM 11 mode. Find the cut-off frequency, and cut-off wavelength. 11. (a)discuss the characteristics of TE, TM and TEM waves between parallel conducting planes. And also derive the cutoff frequency and phase velocity from the propagation constant. (b) Describe the Velocity of propagation of wave between a pair of N-0 perfectly conducting plates. 12. [a] Discuss the characteristics of TE, TM and TEM waves between parallel conducting planes. And also derive the cutoff frequency and phase velocity from the propagation constant. [b] A pair of perfectly conducting planes is separated by 3 cm in air and carries a 10 GHz signal in TM 1 mode. Find the cut-off frequency, Phase constant, cut-off wavelength. 13. Derive the field expressions for the field strengths for Transverse Electric Waves between a pair of parallel perfectly conducting planes of infinite extent in the Y and Z directions. The planes are separated in X direction by a meter. 14. [a] Derive the expressions for the field components of TM waves between parallel conducting plates, propagating in Z direction. [b] For a frequency of 6 GHz and plane separation = 7 cm, find the following for the TE10 mode (1) cut off frequency Group velocity M-0 M-07 M-0 M-07 M- Apr/ May; N- Nov/ Dec Page 12 of 1 (2) Phase and N

13 Sl.No. Question Exam Marks 15. [a] Explain wave impedance and obtain the expressions of wave impedance for TE and TM waves guided along parallel planes. Also sketch the variations of wave impedance with frequency. [b] For a frequency of 5 GHz and plane separation of cm in air, find N the following for TM10 mode: [1] cut-off wavelength [2] Characteristic impedance and [3] Phase constant 16. Parallel perfectly conducting plates are separated by 7 cm in air and M-07 carry a signal with frequency (f) of 6 GHz in TE 1 mode. Find (1) the cut-off frequency (f c ), (2) Phase constant, (3) Attenuation constant and Phase constant for f = 0. f c and (4) cut-off wavelength. 17. Derive the wave impedance for TE waves between parallel planes. M Derive the expressions for the field strength for TE Waves between parallel plates (parallel to XY plane) propagating in Z direction. [b] A parallel plane waveguide with plate separation of 20 cm with the TE10 mode excited at 1 GHz. Find the propagation constant. N Derive the expression for attenuation constant of TE waves in between two parallel conducting planes. [b] A pair of perfectly conducting planes is separated by cm in air. For a frequency of 500 MHz with TM10 mode excited, find the cut-off N-06 frequency, phase shift, phase velocity and group velocity. 20. Deduce expressions for TEM waves in parallel plate waveguides and NEW plot the field configurations. 21. Derive expression for attenuation factor for TEM/TE/TM waves in parallel plate guides. NEW UNIT-V/ PART A :: RECTANGULAR WAVEGUIDES Sl.No. Question Exam 1. Compare transmission line and wave guide. M Calculate the cutoff wavelength for the TM11 mode in a standard rectangular N-10 waveguide if a= 4.5 cm. 3. Give the reason for impossibility of TEM waves in waveguides M Define cutoff wavelength. M A rectangular air filled copper waveguide with dimension of a=2.2cm and N-09 b=1.01cm has a 9.2GHz signal propagated in it. Determine the guide wavelength for TE 10 mode. 6. A waveguide has an internal breadth a of 3cm and carries the dominant mode of a N-09 signal of unknown wavelength. If the characteristics wave impedance is 500 ohms, calculate the signal wavelength. 7. A rectangular waveguide with dimensions a =.5 cm and b = 4.3 cm. Determine the M-09 cut-off frequency for TM 10 mode of propagation.. What is meant by dominant mode of the wave? M How is the TE 10 mode launched or initiated in rectangular wave guide using an open ended coaxial cable? N-0 M Calculate the cut-off frequency of a rectangular wave guide whose inner dimensions N-0 are a = 2.5cm and b = 1.5cm operating at TE 10 mode. M- Apr/ May; N- Nov/ Dec Page 13 of 1

14 Sl.No. Question Exam 11. Write a brief note on Excitation of modes in rectangular waveguides. M Calculate the cut-off wavelength of a rectangular waveguide whose inner M-0 dimensions are a = 2.3 cm and b = 1.03 cm operating in TE 10 mode. 13. A rectangular waveguide with dimensions a =.5 cm and b = 4.3 cm is fed by 5 N-07 GHz carrier. Will a TE 11 mode be propagated? 14. Define wave impedance and write an expression for wave impedance of TE waves N-07 in rectangular waveguide. 15. Why the TE 10 wave is called as dominant wave in rectangular waveguides? M A rectangular waveguide has the following dimensions l = 2.54 cm, b = 1.27 cm, N-06 waveguide thickness = cm. Calculate the cut-off frequency for TE 11 mode. 17. What are dominant mode and degenerate modes in rectangular waveguides? N Define phase velocity. EXTRA 19. What are wave guide modes? EXTRA 20. Define attenuation factor of a wave guide. EXTRA 21. What is a w/g? Mention few applications. EXTRA 22. A rectangular w/g is 1cm X 2 cm in dimensions. Calculate the cutoff wavelength for EXTRA TE10 mode. 23. Write the relation between guide wave length, free space wave length and cutoff EXTRA wave length. 24. What is the configuration of TEM wave in a rectangular w/g? EXTRA 25. Discuss whether True or False: A rectangular w/g acts as a HPF EXTRA UNIT-V/ PART A :: CIRCULAR WAVEGUIDES Sl.No. Question Exam 1. Why should we take the cylindrical co-ordinate system to solve the field equations M-10 for a circular guide? 2. What are the disadvantages of circular waveguides? N Which is the dominant mode in circular waveguide? Why? M-09 M-0 4. Why is the Bessel s function of the second kind (Neumann s function) not N-0 applicable for the field analysis inside the circular wave guide? 5. Write Bessel s function of first kind of order zero. N A circular waveguide operated at 11 GHz has the internal diameter of 4.5 cm. For a N-06 TE 01 mode propagation, calculate λ and λ c [(ha) 01 = 2.405] 7. Which are the degenerate modes in a circular w/g? EXTRA. Which mode has the lowest attenuation in a circular w/g? EXTRA 9. What are Bessel s and Neumann functions? EXTRA 10. A circular w/g has an internal radius of 2.5 Cm.. Find the cutoff frequency for the EXTRA dominant mode. 11. Mention few applications of circular w/gs EXTRA UNIT-V/ PART A :: RESONATORS Sl.No. Question Exam 1. An air filled resonant cavity with dimensions a = 5 cm, b=4 cm, c= 10 cm is made M-11 M- Apr/ May; N- Nov/ Dec Page 14 of 1

15 Sl.No. Question Exam of copper. Find the resonant frequency for the lowest order mode. 2. Give the applications of cavity resonators. N List out the parameters describing the performance of a resonator. M Define a cavity resonator and also give its application. N What does cavity resonator mean? M Distinguish between wave guides and cavity resonator. N-0 7. Define the quality factor of a cavity resonator. M-0 M-07 N-06. What are the applications of cavity resonators? N What is cavity resonator? M Define resonant frequency. EXTRA 11. Define Q-factor [Unloaded / Loaded / externally loaded]. EXTRA 12. Write an expression for the resonant frequency of a rectangular / circular cavity EXTRA resonator. 13. Write an expression for the unloaded Q of a rectangular cavity with square base EXTRA [a=d] for its dominant mode. 14. Write an expression for the unloaded Q of a cubic cavity for its dominant mode. EXTRA 15. Draw the field configuration for the TE101 mode of a rectangular cavity. EXTRA 16. Write an expression for the unloaded Q of a rectangular cavity for its dominant EXTRA mode. UNIT-V/ PART B :: RECTANGULAR WAVEGUIDES Sl.No. Question Exam Marks 1. A rectangular wave guide with dimensions a = 2.5 cm, b = 1 cm is to M operate below 15 GHz. How many TE and TM modes can the waveguide transmit if the guide is filled with a medium characterized by σ = 0, Є= 4Єo and µ r = 1? Calculate the cutoff frequencies of the modes. 2. Explain in detail (i) Excitation of wave guides M (i) Discuss the propagation of TM waves in a rectangular waveguide with relevant expressions and diagrams for the field components. (ii) A rectangular waveguide measuring a = 4.5 cm and b= 3 cm internally has a 9 GHz signal propagated in it. Calculate the guide wave length, phase and group velocities and characteristic impedance for the N dominant mode. 4. (i) Distinguish between TE and TM modes of the rectangular guide.() (ii) Derive the equations to give the relationships among the fields within the rectangular guide. () M (i) A rectangular air-filled copper guide with 0.9inch x 4 inch cross section and 12inch length is operated at 9.2GHz with a dominant mode. Find the cut-off frequency,the phase velocity and the characteristics impedance.() (ii) A standard air-filled rectangular guide with dimensions a=.636cm, b=4.31cm is fed by a 4GHz carrier from a coaxial cable. M-10 M- Apr/ May; N- Nov/ Dec Page 15 of 1

16 Sl.No. Question Exam Marks Determine whether a TE 10 mode is propagated. If so, calculate the phase velocity and the group velocity. () 6. Describe the field components of TE waves in a rectangular waveguide N with necessary expression and also plot the field configurations for the TE 10 mode. 7. (i) A rectangular waveguide measuring a=4.5cm and b=3cm internally has a 9GHz signal propagated in it. Calculate the guide wavelength, phase and group velocities and characteristics wave impedance for TM 11 mode. (ii) Write a brief note on excitation of modes in rectangular waveguides. N Deduce the expressions for the field components of TM waves guided M along a rectangular wave guide. 9. (i) Derive the expression of wave impedance for TE and TM waves guided along rectangular waveguide. (b) A TE 10 mode is propagated through a waveguide with a = 10 cm at a frequency of 2.5 GHz. Find the cut-off wavelength, phase velocity, group velocity and wave impedance. M Derive the field configuration, cut off frequency and velocity of N-0 16 propagation for TE waves in rectangular waveguide. 11. A TE 10 wave at 10GHz propagates in a X-band copper rectangular N-0 16 waveguide with inner dimensions a =2.3 cm and b = 1cm, which is filled with Teflon ε r =2.1, µ r = 1. Calculate the cut-off frequency, velocity of propagation, Phase constant, Guide wavelength, and Phase velocity and wave impedance. 12. Derive the field configuration, cut-off frequency and velocity of M-0 16 propagation for TM waves in rectangular waveguide. M TEM wave cannot exist in a single conductor waveguide Justify the statement using Maxwell s equation. [b] A X-band air filled rectangular waveguide has inner dimension of a=2.3 cm and b=1 cm. Calculate the cut-off frequencies in the following M-0 modes: TE 10, TE 20, TM 11, TM12. Also check which of the modes will propagate along the waveguide when the signal frequency is 10 GHz. 14. [a] Obtain the solution of Electric and Magnetic fields of TM waves guided along rectangular waveguide. [b] A rectangular waveguide measures 3 x 4.5 cm internally and has a 10 GHz signal propagated in it. Calculate the cut-off wavelength, the N guide wavelength and the characteristic wave impedance for the TE 10 mode. 15. [a] Discuss the attenuation of EM waves guided along rectangular waveguide. [b] What are the dimensions of a waveguide with the following specifications? (1) At a frequency of MHz, the guide wavelength N-07 for TE 10 mode is 7.57% of the cut-off wavelength (2) TE 30 and TE 12 mode have the same cut-off frequency. 16. A TE 10 wave at 10GHz propagates with the velocity of 2 x 10 m/sec in a brass σ c = 1.57 x 107 S/m - rectangular waveguide with inner dimensions a =1.5 cm and b = 0.6 cm, which is filled with polyethylene ε r =2.25 µ r = 1. Calculate the Phase constant, Guide wavelength, Phase M M- Apr/ May; N- Nov/ Dec Page 16 of 1

17 Sl.No. Question Exam Marks velocity, and wave impedance. Which signal among two separate signals with frequency of 5 GHz and 15 GHz will be supported by the rectangular waveguide for propagation through it? 17. Determine the solution of electric and magnetic fields of TE waves guided along rectangular waveguide. [b] An air filled rectangular waveguide with dimensions of a =.5 cm and b = 4.3 cm is fed by a 4 GHz carrier from co-axial cable. Determine N the cut-off frequency, phase velocity and group velocity for TE 11 mode. 1. Explain wave impedance of a rectangular waveguide and derive expression for the wave impedance of TE, TM and TEM waves. [b] The cut-off wavelengths of a rectangular waveguide are measured to be cm and 4. cm for TE10 and TE11 mode respectively. Determine waveguide dimensions. N-06 UNIT-V/ PART B :: CIRCULAR WAVEGUIDES Sl.No. Question Exam Marks 1. M M Explain the propagation of electromagnetic waves in a cylindrical N waveguide with suitable expressions. [16] 4. Discuss the propagation of TM waves in a circular waveguide with relevant expression for the field components M (ii) Calculate the cutoff wavelength, guide wavelength and M-10 6 characteristics wave impedance of a circular waveguide with an internal diameter of 4cm for a 10GHz signal propagated in it in the TE 11 mode. 6. (i)derive the solution of field equations using cylindrical coordinates.() (ii) Draw the field configurations of different TM and TE modes for a N -09 circular guide.() 7. (i) Derive the expressions for the field components of TE waves guided along circular waveguide. (b) A circular waveguide has an internal diameter of 6 cm. For a 9 GHz signal propagated init in the TE 11 mode, calculate cut-off frequency and characteristic impedance. [(ha 11 ) = 1.4)] M (i) Derive the expressions for TM wave components in circular waveguide using Bessel function. (b) Write a brief note on excitation of modes in circular wave guides 9. Using Bessel function derive the TE wave components in circular waveguides. [10 M] 10. [a] Determine the solution of electric and magnetic fields TM waves guided along circular waveguide. [10 M] [b] A circular waveguide has an internal diameter of 4 cm. For a 10 GHz signal propagated in it in the TE 11 mode, calculate cut off wavelength, guide wavelength and characteristic impedance. [(ha 11 ) = 1.4)] [6 M] N-0 M M-0 10 N M- Apr/ May; N- Nov/ Dec Page 17 of 1

18 UNIT-V/ PART B :: RESONATORS AWP/ QB/ JAN 2011 Sl.No. Question Exam Marks 1. Explain in detail (ii) Resonant Cavities M M N N M Explain the field components of the TE waves in a rectangular cavity M resonator with relevant expressions. 7. Derive the expression for the field components existing in a rectangular N -09 cavity.(). (i) Obtain the expression for resonant frequency of a rectangular cavity resonator. (b) Calculate the lowest resonant frequency of a rectangular cavity resonator of dimension a =2 cm,b = 1 cm and d =3 cm M Derive the equation for Q-factor of a rectangular cavity resonator for TE 101 mode. 10. Calculate the resonant frequency of an air filled rectangular resonator of dimensions a = 2 cm, b = 4 cm, d = 6 cm operating in TE 101 mode.[6 M 11. Calculate the resonant frequency of a rectangular resonator of dimensions a = 3 cm, b = 2 cm, d = 4 cm if the operating mode is TE 101. Assume free space within the cavity. [ M] 12. Calculate the resonant frequency of an air filled rectangular resonator of dimensions a = 3 cm, b = 2 cm, d = 4 cm operating in TE 101 mode [4 M N-0 M-0 M-07 M-0 N-07 M-07 M- Apr/ May; N- Nov/ Dec Page 1 of 1

19 EC6503 TRANSMISSION LINES AND WAVEGUIDES TWO MARKS QUESTION & ANSWERS UNIT I-TRANSMISSION LINE THEORY 1. Define the line parameters? The parameters of a transmission line are: Resistance (R),Inductance (L),Capacitance (C), Conductance (G),Resistance (R) is defined as the loop resistance per unit length of the wire. Its unit is ohm/km,inductance (L) is defined as the loop inductance per unit length of the wire. Its unit is Henry/Km,Capacitance (C) is defined as the loop capacitance per unit length of the wire. Its unit is Farad/Km,Conductance (G) is defined as the loop conductance per unit length of the wire. Its unit is mho/km 2. What are the secondary constants of a line? Why the line parameters are called distributed elements? The secondary constants of a line are: Characteristic Impedance Propagation Constant.since the line constants R, L, C, G are distributed through the entire length of the line, they are called as distributed elements. They are also called as primary constants. 3. Define Characteristic impedance Characteristic impedance is the impedance measured at the sending end of the line. It is given by Z0 = ГZ/Y, where Z = R + jωl is the series impedance Y = G + jωc is the shunt admittance 4. Define Propagation constant Propagation constant is defined as the natural logarithm of the ratio of the sending end current or voltage to the receiving end current or voltage of the line. It gives the manner in the wave is propagated along a line and specifies the variation of voltage and current in the line as a function of distance. Propagation constant is a complex quantity and is expressed as γ = α + j β The real part is called the attenuation constant Whereas imaginary part of propagation constant is called the phase constant 5. What is a finite line? Write down the significance of this line? A finite line is a line having a finite length on the line. It is a line, which is terminated, in its characteristic impedance (ZR=Z0), so the input impedance of the finite line is equal to the characteristic impedance (Zs=Z0). 6.What is an infinite line? An infinite line is a line in which the length of the transmission line is infinite. A finite line, which is terminated in its characteristic impedance, is termed as infinite line. So for an infinite line, the input impedance is equivalent to the characteristic impedance. 7.What is wavelength of a line? The distance the wave travels along the line while the phase angle is changing through 2π radians is called a wavelength..what are the types of line distortions? The distortions occurring in the transmission line are called waveform distortion or line distortion. Waveform distortion is of two types: a) Frequency distortion b) Phase or Delay Distortion. 9.How frequency distortion occurs in a line? When a signal having many frequency components are transmitted along the line all the frequencies will not have equal attenuation and hence the received end waveform will not be identical with the input waveform at the sending end because each frequency is having different attenuation. This type of distortion is called frequency distortion.

20 10.How to avoid the frequency distortion that occurs in the line? In order to reduce frequency distortion occurring in the line, a) The attenuation constant α should be made inde pendent of frequency. b) By using equalizers at the line terminals which minimize the frequency distortion. Equalisers are networks whose frequency and phase characteristics are adjusted to be inverse to those of the lines, which result in a uniform frequency response over the desired frequency band, and hence the attenuation is equal for all the frequencies. 11.What is delay distortion? When a signal having many frequency components are transmitted along the line, all the frequencies will not have same time of transmission, some frequencies being delayed more than others. So the received end waveform will not be identical with the input waveform at the sending end because some frequency components will be delayed more than those of other frequencies. This tpe of distortion is called phase or delay distortion. 12. How to avoid the frequency distortion that occurs in the line? In order to reduce frequency distortion occurring in the line, a) The phase constant β should be made dependent of frequency. b) The velocity of propagation is independent of frequency. c) By using equalizers at the line terminals which minimize the frequency distortion. Equalizers are networks whose frequency and phase characteristics are adjusted to be inverse to those of the lines, which result in a uniform frequency response over the desired frequency band, and hence the phase is equal for all the frequencies. 13.What is a distortion less line? What is the condition for a distortion less line? A line, which has neither frequency distortion nor phase distortion is called a distortion less line The condition for a distortion less line is RC=LG. Also, a) The attenuation constant should be made independent of frequency. b) The phase constant should be made dependent of frequency. d) The velocity of propagation is independent of frequency. 14.What is the drawback of using ordinary telephone cables? In ordinary telephone cables, the wires are insulated with paper and twisted in pairs, therefore there will not be flux linkage between the wires, which results in negligible inductance, and conductance. If this is the case, the there occurs frequency and phase distortion in the line. 15.How the telephone line can be made a distortion less line? For the telephone cable to be distortion less line, the inductance value should be increased by placing lumped inductors along the line. 16.What is Loading? Loading is the process of increasing the inductance value by placing lumped inductors at specific intervals along the line, which avoids the distortion 17.What are the types of loading? a) Continuous loading b) Patch loading c) Lumped loading 1.What is continuous loading? Continuous loading is the process of increasing the inductance value by placing a iron core or a magnetic tape over the conductor of the line. 19.What is patch loading? It is the process of using sections of continuously loaded cables separated by sections of unloaded cables which increases the inductance value 20.What is lumped loading? Lumped loading is the process of increasing the inductance value by placing lumped inductors at specific intervals along the line, which avoids the distortion